Metal cap sorter

ABSTRACT

Apparatus and method for sorting foreign closures from a stream of closures being fed into a capping machine. A light source is positioned at an acute angle with respect to the horizontal plane defined by the top panel of a metal closure. A light sensing unit is positioned at an angle with respect to the horizontal plane less than the angle of spectral reflection of the light from the light source. It has been found that each of a plurality of metal closures has unique light-scattering properties which may be measured by the light sensing unit positioned off of the angle of reflection of the light source. By introducing a plurality of closures into the light beam, a level may be established for each of the closures. By setting an electronic logic unit sensitive to the scattered light level of a particular desired closure, foreign closures which fall above or below this preset level may be rejected by a rejection mechanism. The rejection mechanism most frequently takes the form of a puff of compressed air to blow foreign closures from a line of closures being fed into a capping machine. The apparatus further includes a series of filters positioned over the light source to reduce the amount of light to an intensity level to which the light sensing unit is responsive.

United States Patent [191 Senesky [451 Feb. 5, 1974 [52] US. Cl. 209/111.6, 356/186 [51] Int. Cl. 1307c 5/342 [58] Field of Search 209/1 1 1.6, 111.7; 356/18 G,

[56] References Cited UNITED STATES PATENTS 3,097,744 7/1963 l-lutter et al. 209/111.6 2,988,219 6/1961 Bartlett 209/111 6 2,967,497 l/l961 Braon et al. 209/111.7 X 2,165,054 7/1939 Johnson 356/18 G 3,555,287 l/l971 Schmermund 356/209 3,069,013 12/1962 Neubrech et a]. 209/111.6

Primary ExaminerRichard A. Schacher Assistant Examiner-Gene A. Church Attorney, Agent, or Firm-Steve M. McLary; A. J. Steger; E. .l. Holler [57] ABSTRACT Apparatus and method for sorting foreign closures from a stream of closures being fed into a capping machine. A light source is positioned at an acute angle with respect to the horizontal plane defined by the top panel of a metal closure. A light sensing unit is positioned at an angle with respect to the horizontal plane less than the angle of spectral reflection of the light from the light source. It has been found that each of a plurality of metal closures has unique light-scattering properties which may be measured by the light sensing unit positioned off of the angle of reflection of the light source. By introducing a plurality of closures into the light beam, a level may be established for each of the closures. By setting an electronic logic unit sensitive to the scattered light level of a particular desired closure, foreign closures which fall above or below this preset level may be rejected by a rejection mechanism. The rejection mechanism most frequently takes the form of a puff of compressed air to blow foreign closures from a line of closures being fed into a capping machine. The apparatus further includes a series of filters positioned over the light source to reduce the amount of light to an intensity level to which the light sensing unit is responsive.

2 Claims, 2 Drawing Figures mamas 51974 3.789.983

FIG. 2

INVENTOR. ALBERT PScmes w METAL CAP SORTER BACKGROUND OF THE INVENTION sorting of foreign closures from a plurality of desired 1 closures by measuring the light scattered from the top panel of the closure and rejecting those closures whose scattered light value is above or below the unique value for the desired closure.

In the manufacture of metal closures, it is not unusual for foreign closures to be introduced'into a group ofclosures being made. This may occur due to the proximity of presses stamping out different closures which may allow closures from adjacent presses to become intermmixed. Theintermixing is seldom of a large magnitude, but foreign caps, if introduced into a capping machine in a bottling plant, can cause the capping machine to jam. In addition, closure hoppers in bottling plants are frequently used for more than one type ofrclosure. It often occurs that a closure from a previous bottling run may remain trapped within the hopper or within the feed system, thereby allowing such foreign closure to be introduced into a subsequent capping operation. The effect, in such a case, is alsoto cause amajamming of the capping machine, which would have been set up to accept only the closure for the currentcapping operation. At the present nt time, foreign .caps are detected only by a human operator standingby the cap feed line and visually observing foreign caps and removing :them from the feed line. This, of course, is .an inefficient and expensive process, since the human operator is subject to error and may on occasion miss the presence .of foreign caps. The present invention presents an apparatus which automatically sorts caps and rejects any foreign caps from the line feeding the capping machine. SUM- MARY OF THE INVENTION I have found that painted metal closures possess unique light-scattering properties which may be measured, evaluated, and utilized to reject foreign closures from a continuing stream of closures being fed to a capping machine. A light source is positioned at an acute angle with respectto a horizontal plane designed by the top panel of a closure A light-sensitive detection unit is then positioned opposite the light source at an angle less than the angle of spectral reflection of the light from the light source. Individual closures are then placed into the path of the light beam andtheir scattering properties are measured by the light sensitive detection unit. Having once determined the unique scatteringvalue of the closure, an electronic logic unit may be set to reject closures which give scattered light values 5 above or below the unique preset level. By connecting the electronic gate to a rejection unit, foreign closures may be rejected as a stream of closures are passed one-at-a-time under the lightsource.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of the apparatusof the present invention as his used todetermine the unique llightt-scattering properties of v eachclosure;

FIG. 2 is a plan view of tthe apparatus of the present invention as it would be utilized in conjunction with the feeding of a series of closures to a capping machine.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the preferred embodiment of the invention shown in F IGG. l a source of lightt 10 is positioned over a stationary flat surface 12 at an acute angle by suitable sup- 0 port means (not shown). In addition, a light sensing unit 14 is also positioned over the fiat surface 12 at an acute angle less than the spectral angle of reflection of light from the light source 10 by the same support means used to carry the light source 1010. In this prefeferred embodiment, the light source 10 is positioned at an angle of with respect to the plane of the flat surface 12. The sensing unit 14 is positioned at an angle of 30 with respect to the flat surface 12. The light source 10 is made up of a c number of components. A 12 volt incandescent lamp 16 is held in place in a suitable lamp holder 18. A lens tube 20 is telescopingly engaged over the lamp holder 18. t The lens tube 20 serves to carry a piano-convex lens 22 which is used to focus the light emanating from the incandescentlamp 16. In addition, a series of three filters 24, 25 and 26 are positioned near the end of the lens tube 20. The filter 24 is a Roscolene No. 871; the filter 25 is a Roscolene 874; and the filtter 26 is a Roscolene No. 878.

tThe filters 24, 25 and 26 are all manufactured by Rosco Laboratories, Inc., Port Chester, NY. The net effect of the filters 24, 25 and 26 is to filter out all the light emanating from the incandescent lamp 16 except that light falling within the 4800 to 4600 Angstrom wavelength range. Th This light is green in color. The particular color oof light transmitted by the light source10 is not critical for proper 0 operation of this invention. The filters 24, 25 and 26 serve merely to reduce the intensity of light issuing from the light source 10 to a level which is acceptable to a photo transistor 28 mounted within the light sensing unit 14. The light sensing unit 14 itself is also made up of several component parts. A support tube 30 forms the major framework for the sensing unit 14. Mounted within the support tube 30 is the phe photo transistor 28 which is an LS-6OO photo transistor manufactured by the General Sensors Corporation of Athens, Texas. The photo transistor 28 is of the type whose resistance varies s a function of the amount of light incident on it. Also mounted within the support tube 30 is a double convex lens 32 and a plano-convex lens 34 which are used to focus incoming light on the photo transistor 28. In addition, an infrared filter 36 is mounted at the entrance to the mounting tube 30. The purpose of the infraredfilter 36 is to filter out all wavelengths above 7500 Angstroms. This was found necessary because of the effect oof various ambient light sources on the sensitivity and discrimination of the photo transistor 28. That is, some random light-scatteringeffects were found in the infrared region, due tolighting in the environment in which the present invention is used. The output of the photo transistor 28 is through a suitable electric wiring network 38 8 into an ohmeter 40 in the embodiment shown in FIG. 1. The configuration shown in FIG. 1 may beused to measure the uniique light-scattering properties of a plurality of cllosures 42 for use in determining a level of acceptance or rejection when inspecting a plurality of moving closures 42. I have found that,

when a closure 42 is pis placed within the light emananting from the light sourcce 10, a certain percentage of the light incident on the closure 42 is reflected back at the angle of incidence as would normally be expected from physical principles. However, in addition to this well-known and expected spectral reflection, there is also a certain degree of light scattering present. I have determined that the amount of light scattered is a pproperty unique to the closures which I have investigated. It is, therefore, possible to determine the unique light-scattering properties of a plurality of unlike closures using this apparatus. In operation, a closure 42 is placed within thelight emanating from the light source 10, and the response of the photo transistor 28 is observed on the ohmeter 40. The characteristics of the photo transistor 28 are such that its resistance varies dependingon the amount of light incident upon it. Because of the unique light-scattering properties of each specific closure, the resistance of the photo transistor 28 will be different for different types of closures. The results obtained for eleven different types of closures are shown in Tables 1 and 2.

TABLE 1 Sample NUMBER DESCRIPTION 1 34 mm diameter closure 20 mm wide center panel separated by a l mm deep groove which is I mm wide outer section is painted blue with aluminum lettering center section is aluminum with blue lettering 2 37 mm diameter closure painted yellow 3 47 mm diameter closure 31 mm diameter center panel set off by a raised bead 3 mm wide and 2 mm high closure painted brown 4 47 mm diameter closure raised bead 2 mm wide and 2 mm deep about circumference of closure periphery painted yellow 5 47 mm diameter closure painted white background with red lettering 6 4] mm diameter closure painted blue 7 34 mm diameter closure physically identical to number I, but painted white overall 8 37 mm diameter closure painted white background with green lettering 3 mm diameter closure burnished aluminum I0 37 mm diameter closure painted matte gold l l 37 mm diameter closure painted white background with blue lettering TABLE 2 SAMPLE NUMBER RESISTANCE READING BY OHMETER I 20 K .0 2 10 K O 3 16 K O 4 II K (I 5 9,5 K O 6 12 K 9 7 8 K O 8 12.5 K O 9 9 K .0 IO 6 K l I 9 K O In Table 1, if no physical description of the top panel of the closure is given, the top panel was a smooth flat surface. Particular note should be paid to Sample Nos. 1 and 7. These closures are identical except for the type of paint on the top of the closure. It is believed that the scattering effect is a function of the type of paint and its color on the top of each closure. It should also be noted that Samples 2, 8, 10 and l l are also identical in size and configuration, but are unlike in the type of paint placed on the top of the closure. It will be noted from Table 2 that closures 9 and 11 gave identical results seeming to contradict the unique light-scattering properties attributed to each specific closure. However, closure 9 was an unpainted closure having a brushed aluminum top. The direction in which the burnishing marks appear on the top of closure No. 9 appear to have a significant effect on the light-scattering properties of such a closure. Therefore, this apparatus is not usable with respect to such closures but may be used with any painted closure to discriminate and select one specific closure from other unlike closures if the top surfaces of the closures are paintedto present a uniform reflecting surface.

Turning now to FIG. 2, a plurality of supposedly identical closures 42 are conveyed toward a capping machine in the direction shown by the arrow by a suitable conveying means 44. The conveying means 44 may be a belt-type conveyor or may be an inclined chute down which the closures 42 slide. As the closures progress, they pass under a light source 10 and a sensing unit 14, as shown in FIG. 1, which are supported from the conveying means 44 by suitable support brackets 46 and 47. An elevational view of FIG. 2 would show a configuration of the light source 10 and the sensing unit 14 as identical to that shown in FIG. 1, with the closures passing under the two units 10 and 14 with their top surface essentially parallel to the conveying means 44. In FIG. 2, the ohmeter 40 has been replaced by a logic and discrimination unit 48 which receives the output from the photo transistor28 through the electrical wiring network 38. The logic and discrimination unit 48 is of the type well known in the electronic arts which will give no output so long as the input furnished through the electrical wiring network 38 remains within a specified preset value. In the operation of the present invention, the preset value is determined by the resistance caused by light scattering of the specific closure which is to be fed into the capping machine. Any foreign or unlike closures which may be transported by the conveying means 44 will cause the photo transistor 28 to give an output different than that preset in the logic and discrimination unit 48. Should this occur, an output from the logic and discrimination unit 48 will be transferred by electrical wiring means 50 to a rejection means 52. In this preferred embodiment, the rejection means 52 comprises a normally closed air solenoid valve 53 and a directional nozzle 56 connected to an output port of the solenoid valve 53. How ever, the rejection means 52 could take the form of a reciprocating rod, a swinging gate or similar device suitable for removing an individual unlike closure 42 from the stream of closures 42. Air under pressure is furnished through a pipe 54 to the solenoid valve 53. Upon signal from the logic and discrimination unit 48, the solenoid valve 53 will open, allowing compressed air to flow outward through the nozzle 56. The blastof high-pressure air emanating from the nozzle 56 will blowa foreign closure 42 from the conveying means 44 and prevent its entry into the capping machine and subsequent jamming of the capping machine.

What I claim is:

1. A method of sorting metal closures having a painted upper surface comprising the steps of:

a moving a series of unlike closures one at a time past a fixed point;

b. illuminating the top panel of said unlike closures 5 one-at-a-time with a light source positioned at an acute angle with respect to a horizontal plane defined by the top panel of said closures;

c. positioning a light sensing unit to receive lightscattered by said closure at an acute angle with respect to said horizontal plane less than the angle of spectral reflection of the light from said light source;

d. blocking all radiation aboge 7500 Angstroms from entry into said light sensing unit;

e. measuring the response of said sensing unit to light scattered by each of said unlike closures;

f. ceasing the movement of said unlike closures; g. connecting said light sensing unit to an electronic logic and discrimination means;

setting said electronic logic and discrimination means to produce an output in response to light level signals from said light sensing unit above and below the measured signal produced by a specific one of said unlike closures;

connecting a rejection means responsive to an output from said logic and discrimination means to said logic and discrimination means;

j. feeding a plurality of said specific closurespast said light source and said light sensing unit to present scattered light signals to said logic and discrimination means;

k. rejecting all closures which pass said light source and light sensing unit whose scattered light level falls above and below the signal level set in said logic and discrimination means.

2. Apparatus for sorting metal closures having painted top panels comprising, in combination: means for conveying a plurality of closures in single file; a light source positioned above said conveying means at an acute angle with respect to a horizontal plane defined by the top panel of said closures for illuminating the top panel of said closures a light sensing unit positioned above said conveying means at an acute angle with respect to said horizontal plane less than the angle of spectral reflection from said closures for sensing light scattered from said closures, said light sensing unit comprising, a support tube, a phototransistor mounted within said support tube, a lens system mounted within said support tube for focusig scattered light on said phototransistor, and a filter mounted on said support tube 0 remove all scattered radiation above 7500 Angstroms before said scattered radiation impinges on said phototransistor; electronic logic and discrimination means connected to said light sensing unit to give an output signal upon receipt of an indication of light scatteringabove and below a preset value; and rejection meansconnected to said electronic logic and discrimination means and operable upon receipt of an output signal from said electronic logic and discrimination means for rejecting closures exhibiting light scattering above and below said preset value.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,789,983 Dated February 5 1974 Inventor(s) Albert P. Senesky It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Cancel the originally printed columns 1 through 6 and substitute the corrected columns 1 through 6.

Signed and sealed this 27th day of August 1974.

(SEAL) Attest:

McCOY M. GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FQRM Podoso (m'eg) l USCOMM-DC 60376-P69 v F U.S. GOVERNMENT PRINTING OFFICE I I9, 0-36-33.

BACKGROUND OF THE INVENTION This invention generally relates to the sorting of closures for containers. More specifically, this invention relates to the sorting of metal closures utilizing the unique light-scattering properties of each individual closure. Most particularly, this invention relates to the sorting of foreign closures from a plurality of desired closures by measuring the light scattered from the top panel of the closure and rejecting those closures whose scattered light value is above or below the unique value for the desired closure.

In the manufacture of metal closures, it is not unusual for foreign closures to be introduced into a group of closures being made. This may occur due to the proximity of presses stamping out different closures which may allow closures from adjacent presses to become intermixed. The intermixing is seldom of a large magnitude, but foreign caps, if introduced into a capping machine in a bottling plant, can cause the capping machine to jam. In addition, closure hoppers in bottling plants are frequently used for more than one type of closure. It often occurs that a closure from a previous bottling run may remain trapped within the hopper or within the feed system, thereby allowing such foreign closure to be introduced into a subsequent capping operation. The effect, in such a case, is also to cause a jamming of the capping machine, which would have been set up to accept only the closure for the current capping operation. At the present time, foreign caps are detected only by a human operator standing by the cap feed line and visually observing foreign caps and removing them from the feed line. This, of course, is an inefficient and expensive process, since the human operator is subject to error and may on occasion miss the presence of foreign caps. The present invention presents an apparatus which automatically sorts caps and rejects any foreign caps from the line feeding the capping machine.

SUMMARY OF THE INVENTION l have found that painted metal closures possess unique light-scattering properties which may be measured, evaluated, and utilized to reject foreign closures from a continuing stream of closures being fed to a capping machine. A light source is positioned at an acute angle with respect to a horizontal plane designed by the top panel of a closure. A light-sensitive detection unit is then positioned opposite the light source at an angle less than the angle of spectral reflection of the light from the light source. Individual closures are then placed into the path of the light beam and their scattering properties are measured by the light sensitive detection unit. Having once determined the unique scattering value of the closure, an electronic logic unit may be set to reject closures which give scattered light values above or below the unique preset level. By connecting the electronic gate to a rejection unit, foreign closures may be rejected as a stream of closures are passed oneat-a-time under the light source.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of the apparatus of the present invention as it is used to determine the unique light-scattering properties of each closure;

FIG. 2 is a plan view of the apparatus of the present invention as it would be utilized in conjunction with the feeding of a series of closures to a capping machine.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the preferred embodiment of the invention shown in FIG. 1 a source of light 10 is positioned over a stationary flat surface 12 at an acute angle by suitable support means (not shown). In addition, a light sensing unit 14 is also positioned over the flat surface 12 at an acute angle less than the spectral angle of reflection of light from the light source 10 by the same support means used to carry the light source 10. In this preferred embodiment, the light source 10 is positioned at an angle of with respect to the plane of the flat surface 12. The sensing unit 14 is positioned at an angle of 30 with respect to the flat surface 12. The light source 10 is made up of a number of components. A 12 volt incandescent lamp 16 is held in place in a suitable lamp holder 18. A lens tube 20 is telescopingly engaged over the lamp holder 18. The lens tube 20 serves to carry a plano-convex lens 22 which is used to focus the light emanating from the incandescent lamp 16. In addition, a series of three filters 24, 25 and 26 are positioned near the end of the lens tube 20. The filter 24 is a Roscolene No. 871; the filter 25 is a Roscolene 874; and the filter 26 is a Roscolene No. 878. The filters 24, 25 and 26 are all manufactured by Rosco Laboratories, Inc., Port Chester, NY. The net effect of the filters 24, 25 and 26 is to filter out all the light emanating from the incandescent lamp 16 except that light falling within the 4800 to 4600 Angstrom wavelength range. This light is green in color. The particular color of light transmitted by the light source 10 is not critical for proper operation of this invention. The filters 24, 25 and 26 serve merely to reduce the intensity of light issuing from the light source 10 to a level which is acceptable to a photo transistor 28 mounted within the light sensing unit 14. The light sensing unit 14 itself is also made up of several component parts. A support tube 30 forms the major framework for the sensing unit 14. Mounted within the support tube 30 is the photo transistor 28 which is an LS-600 photo transistor manufactured by the General Sensors Corporation of Athens, Texas. The photo transistor 28 is of the type whose resistance varies as a function of the amount of light incident on it. Also mounted within the support tube 30 is a double convex lens 32 and a plano-convex lens 34 which are used to focus incoming light on the photo transistor 28. In addition, an infrared filter 36 is mounted at the entrance to the mounting tube 30. The purpose of the infrared filter 36 is to filter out all wavelengths above 7500 Angstroms. This was found necessary because of the effect of various ambient light sources on the sensitivity and discrimination of the photo transistor 28. That is, some random lightscattering effects were found in the infrared region, due to lighting in the environment in which the present invention is used. The output of the photo transistor 28 is through a suitable electric wiring network 38 into an ohmeter 40 in the embodiment shown in FIG. 1. The configuration shown in FIG. 1 may be used to measure the unique light-scattering properties of a plurality of closures 42 for use in determining a level of acceptance or rejection when inspecting a plurality of moving closures 42. I have found that, when a closure 42 is placed within the light emanating from the light source 10, a certain percentage of the light incident on the closure 42 is reflected back at the angle of incidence as would normally be expected from physical principles. However, in addition to this well-known and expected spectral reflection, there is also a certain degree of light scattering present. I have determined that the amount of light scattered is a property unique to the closures which I have investigated. It is, therefore, possible to determine the unique light-scattering properties of a plurality of unlike closures using this apparatus. In operation, a closure 42 is placed within the light emanating from the light source 10, and the response of the photo transistor 28 is observed on the ohmeter 40. The characteristics of the photo transistor 28 are such that its resistance varies depending on the amount of light incident upon it. Because of the unique light-scattering properties of each specific closure, the resistance of the photo transistor 28 will be different for different types of closures. The results obtained for eleven different types of closures are shown in Tables 1 and 2.

TABLE 1 SAMPLE NUMBER DESCRIPTION I 34 mm diameter closure 20 mm wide center panel separated by a 1 mm deep groove which is 1 mm wide outer section is painted blue with aluminum lettering center section is aluminum with blue lettering 2 37 mm diameter closure painted yellow 3 47 mm diameter closure 31 mm diameter center panel set off by a raised bead 3 mm wide and 2 mm high closure painted brown 4 47 mm diameter closure raised bead 2 mm wide and 2 mm deep about circumference of closure periphery painted yellow 5 47 mm diameter closure painted white background with red lettering 6 41 mm diameter closure painted blue 7 34 mm diameter closure physically identical to number I. but painted white overall 8 37 mm diameter closure painted White background with green lettering 9 3 mm diameter closure burnished aluminum I 37 mm diameter closure painted matte gold 37 mm diameter closure painted white background with blue lettering TABLE 2 RESISTANCE READING BY OHMETER SAMPLE NUMBER 6 size and configuratlon, but are unlike in the type of paint placed on the top of the closure. It will be noted from Table 2 that closures 9 and l 1 gave identical results seeming to contradict the unique light-scattering properties attributed to each specific closure. However, closure 9 was an unpainted closure having a brushed aluminum top. The direction in which the burnishing marks appear on the top of closure No. 9 appear to have a significant effect on the light-scattering properties of such a closure. Therefore, this apparatus is not usable with respect to such closures but may be used with any painted closure to discriminate and select one specific closure from other unlike closures if the top surfaces of .the closures are painted to present a uniform reflecting surface.

Turning now to FIG. 2, a plurality of supposedly identical closures 42 are conveyed toward a capping machine in the direction shown by the arrow by a suitable conveying means 44. The conveying means 44 may be a belt-type conveyor or may be an inclined chute down which the closures 42 slide. As the closures progress, they pass under a light source 10 and a sensing unit 14, as shown in FIG. 1, which are supported from the conveying means 44 by suitable support brackets 46 and 47. An elevational view of FIG. 2 would show a configuration of the light source 10 and the sensing unit 14 as identical to that shown in FIG. 1, with the closures passing under the two units 10 and 14 with their top surface essentially parallel to the conveying means 44. In FIG. 2, the ohmeter 40 has been replaced by a logic and discrimination unit 48 which receives the output from the photo transistor 28 through the electrical wiring network 38. The logic and discrimination unit 48 is of the type well known in the electronic arts which will give no output so long as the input furnished through the electrical wiring network 38 remains within a specified preset value. In the operation of the present invention, the preset value is determined by the resistance caused by light scattering of the specific closure which is to be fed into the capping machine. Any foreign or unlike closures which may be transported by the conveying means 44 will cause the photo transistor 28 to give an output different than that preset in the logic and discrimination unit 48. Should this occur, an output from the logic and discrimination unit 48 will be transferred by electrical wiring means 50 to a rejection means 52. In this preferred embodiment, the rejection means 52 comprises a normally closed air solenoid valve 53 and a directional nozzle 56 connected to an output port of the solenoid valve 53. However, the rejection means 52 could take the form of a reciprocating rod, a swinging gate or similar device suitable for removing an individual unlike closure 42 from the stream of closures 42. Air under pressure is furnished through a pipe 54 to the solenoid valve 53. Upon signal from the logic and discrimination unit 48, the solenoid valve 53 will open, allowing compressed air to flow outward through the nozzle 56. The blast of high-pressure air emanating from the nozzle 56 will blow a foreign closure 42 from the conveying means 44 and prevent its entry into the capping machine and subsequent jamming of the capping machine.

What I claim is:

l. A method of sorting metal closures having a painted upper surface comprising the steps of:

a. moving a series of unlike closures one at a time past a fixed point;

b. illuminating the top panel of said unlike closures one-at-a-time with a light source positioned at an acute angle with respect to a horizontal fined by the top panel of said closures;

c. positioning a light sensing unit to receive light scattered by said closure at an acute angle with respect to said horizontal plane less than the angle of spectral reflection of the light from said light source;

d. blocking all radiation above 7500 Angstroms from entry into said light sensing unit;

e. measuring the response of said sensing unit to light scattered by each of said unlike closures;

f. ceasing the movement of said unlike closures;

g. connecting said light sensing unit to an electronic logic and discrimination means;

h. setting said electronic logic and discrimination means to produce an output in response to light level signals from said light sensing unit above and below the measured signal produced by a specific one of said unlike closures;

. connecting a rejection means responsive to an output from said logic and discrimination means to said logic and discrimination means;

. feeding a plurality of said specific closures past said light source and said light sensing unit to present scattered light signals to said logic and discrimination means;

k. rejecting all closures which pass said light source and light sensing unit whose scattered light level falls above and below the signal level set in said plane delogic and discrimination means.

2. Apparatus for sorting metal closures having painted top panels comprising, in combination: means for conveying a plurality of closures in single file; a light source positioned above said conveying means at an acute angle with respect to a horizontal plane defined by the top panel of said closures for illuminating the top panel of said closures; a light sensing unit positioned above said conveying means at an acute angle with respect to said horizontal plane less than the angle of spectral reflection from said closures for sensing light scattered from said closures, said light sensing unit comprising, a support tube, a. phototransistor mounted within said support tube, a lens system mounted within said support tube for focusing scattered light on said phototransistor, and a filter mounted on said support tube to remove all scattered radiation above 7500 Angstroms before said scattered radiation impinges on said phototransistor; electronic logic and discrimination means connected to said light sensing unit to give an output signal upon receipt of an indication of light scattering above and below a preset value; and rejection means connected to said electronic logic and discrimination means and operable upon receipt of an output signal from said electronic logic and discrimination means for rejecting closures exhibiting light scattering above and below said preset value. 

1. A method of sorting metal closures having a painted upper surface comprising the steps of: a. moving a series of unlike closures one at a time past a fixed point; b. illuminating the top panel of said unlike closures one-at-atime with a light source positioned at an acute angle with respect to a horizontal plane defined by the top panel of said closures; c. positioning a light sensing unit to receive light scattered by said closure at an aCute angle with respect to said horizontal plane less than the angle of spectral reflection of the light from said light source; d. blocking all radiation above 7500 Angstroms from entry into said light sensing unit; e. measuring the response of said sensing unit to light scattered by each of said unlike closures; f. ceasing the movement of said unlike closures; g. connecting said light sensing unit to an electronic logic and discrimination means; h. setting said electronic logic and discrimination means to produce an output in response to light level signals from said light sensing unit above and below the measured signal produced by a specific one of said unlike closures; i. connecting a rejection means responsive to an output from said logic and discrimination means to said logic and discrimination means; j. feeding a plurality of said specific closures past said light source and said light sensing unit to present scattered light signals to said logic and discrimination means; k. rejecting all closures which pass said light source and light sensing unit whose scattered light level falls above and below the signal level set in said logic and discrimination means.
 2. Apparatus for sorting metal closures having painted top panels comprising, in combination: means for conveying a plurality of closures in single file; a light source positioned above said conveying means at an acute angle with respect to a horizontal plane defined by the top panel of said closures for illuminating the top panel of said closures; a light sensing unit positioned above said conveying means at an acute angle with respect to said horizontal plane less than the angle of spectral reflection from said closures for sensing light scattered from said closures, said light sensing unit comprising, a support tube, a phototransistor mounted within said support tube, a lens system mounted within said support tube for focusing scattered light on said phototransistor, and a filter mounted on said support tube to remove all scattered radiation above 7500 Angstroms before said scattered radiation impinges on said phototransistor; electronic logic and discrimination means connected to said light sensing unit to give an output signal upon receipt of an indication of light scattering above and below a preset value; and rejection means connected to said electronic logic and discrimination means and operable upon receipt of an output signal from said electronic logic and discrimination means for rejecting closures exhibiting light scattering above and below said preset value. 